A man prays at a temple in Rangoon, Burma, where men and women are expected to dress and behave conservatively. Photograph: AFP/Getty Images

The nightclub is heaving, sweaty and loud, pulsating with blinding blue and white lights, and packed with drunken dancers. At the bar, the young sons of Burma's elite are buying bottles of Jack Daniel's and Johnnie Walker with thick wads of dirty kyat notes.

But inside the double doors and through the dark fog of the smoke machine, a cultural transformation is taking place on the dance floor. Clubbers are grinding up against each other – girls on girls, boys on boys – singing along to American hip-hop blaring out of the giant speakers in the corner.

In a country that still criminalises homosexual activity – a legacy from when the British once ruled this country of 50 million – such sights have long been kept out of view. But as Burma slowly opens up, many of its lesbian, gay, bisexual and transgender (LGBT) population are hoping they will no longer have to stay in the shadows.

"When we cruise, we cruise with everyone else – gay or straight – because we don't have 100% gay venues here," says Chitoo, 33, a gay Burmese living in Rangoon. "If we did, the government would arrest us. But now Daw [Aung San] Suu [Kyi] is bringing human rights on to the table, and through her our voices will be louder than ever before."

Some expect the change to be rapid, such as Douglas Thompson, a gay activist who founded the LGBT-friendly travel company Purple Dragon 15 years ago and has been operating tours in Burma and other south Asian countries ever since. "If it's anything like India or China or Vietnam … when things begin to open up, people meet and communicate," he says. "Gay is an idea that people bring with them. It's a lifestyle that is really for most people [in Burma] still completely alien."

Activists say the culture of repression that has long existed in Burma – thanks to an autocratic military junta that ruled the nation for nearly 50 years – prevents many LGBT people from coming out, for fear of being ostracised by their families as much as targeted by police.

Authorities operate under the archaic 19th-century penal code 377, which criminalises "intercourse against the order of nature" and is punishable by up to 10 years in prison. Ambiguously worded laws are also used at whim to arrest, harass and intimidate anyone suspected of "doubtful acts", says Aung Myo Min, of Thailand-based advocacy group Human Rights Education Institute of Burma.

Yet slowly, Burma's LGBT community is gaining ground. Last year Burma got its first LGBT-targeted TV programme, Colours Rainbow TV, which airs once a month online and focuses on LGBT news, interviews and features from Burma and the rest of the world. Aung Myo Min's charity, which created it, estimates that it has 3,000 regular viewers within Burma, but admits the audience is limited to those who can afford internet access and have electricity – just 25% of Burma is on the national power grid. The organisation also publishes a quarterly magazine, Colours Rainbow, and distributes it free within Burma.

The suppression of the LGBT community has public health, as well as human rights, implications. According to UNAids, HIV/Aids affects roughly 240,000 people in Burma, or 0.6% of the population. But that number jumps to 29% for gay men, and the Rangoon-based Aids Alliance estimates that fewer than 20% of the 76,000 people needing anti-retroviral treatment are receiving it.

Activists blame Burma's repressive political environment, which for decades severely limited the number of international organisations and donors able to operate within its closed borders.

"The international assistance we've got right now is very low compared to other countries, and stigma is still very high, even in many donor organisations," says Nyi Nyi, a gay HIV/Aids activist working in Rangoon.

In a nation in effect long cut off from the rest of the world, Burmese society is far more conservative than its more outwardly sexualised neighbour, Thailand. Here, both men and women wear long cotton sarongs called longyi, with women taking pains to cover their shoulders and chest. Premarital sex is frowned upon and traditional beliefs are the norm, especially in rural areas, says Chitoo. "It's common for people to believe that a gay man had a bad relationship with a woman in a past life, so in this life he's punished by being 'turned' gay," he says.

"Corrective" behaviour targeted at LGBT people is common, say rights groups, with even rape used against lesbians, while families may send a gay son to the monastery to "correct" his sexual orientation.

Some names have been changed. Esmer Golluoglu is the pseudonym of a journalist working in Rangoon